Peroxy acids, and peroxyacetic acid in particular, have been used for cleaning and disinfecting various surfaces and implements, including medical devices such as endoscopes, and environmental surfaces, including countertops, ductwork, etc. However, one drawback associated with the use of solutions of peroxyacetic acid and other peroxy acids in general is that the shelf life of such solutions is limited to a few months, due to the inherent instability of the materials. Even very low concentrations of the peroxyacetic species, such as those used to disinfect surfaces (i.e., 0.05% to about 5%) are too unstable for a useful commercial shelf life.
One way to overcome shelf life issues may be to employ a solid formulation which is mixed with water shortly before needed. Active precursor components, including a solid form of hydrogen peroxide such as an alkali metal or alkaline earth metal percarbonate or perborate salt can be combined with an acyl donor, such as either tetraacetylethylenediamine (“TAED”) or acetylsalicylic acid (“ASA”) to yield a peroxy acid according to the scheme conducted in aqueous media:
the peroxide being present from reaction of the perborate or percarbonate with water, which is subsequently available to react with the acyl compound. In the foregoing reaction, the radical X represents the remaining residue of the TAED or ASA molecule, such as in the case of ASA wherein it represents the ASA molecule minus the acetyl group. However, we do not consider TAED and ASA to be efficient acylating agents, in that a relatively large mass of useless carbon-containing byproducts are generated when these reactants are employed. In addition, the kinetics of the reaction are not as favorable as would be desired, because quick generation of appreciable quantities of peroxyacetic acid from ASA according to the above scheme requires a reaction temperature above room temperature.
While peroxyacetic acid has been used to disinfect medical equipment such as endoscopes and related items, peroxypropionic acid (“PPA”) has not been developed for such purposes. Precursors according to one embodiment of the present invention have the distinct advantage that they can be used to easily produce novel antimicrobial formulations which contain PPA, as well as a whole host of other peroxy acids which consume less weight of hydrogen peroxide during their production per mole of peroxy acid produced, than commercial precursors acetyl salicylic acid (ASA) and tetraacetylethylenediamine (TAED). Additionally, precursors according to an embodiment of the present invention allow for the formulation of antimicrobial compositions that have room temperature stability in their concentrated forms, and which can alternatively be packaged in dry powder form for reconstitution by combination with hydrogen peroxide, or a hydrogen peroxide precursor/water mixture at the site of their end use. The resulting peroxide-containing liquids can be readily delivered in liquid or gaseous form at the site of use. The dry powder form of a compound according to one embodiment, or its concentrate may also be applied to the site of use and activated with hydrogen peroxide or water in combination with a hydrogen peroxide precursor.
Thus, in summary, provided are novel water-soluble precursors useful for efficiently generating peroxy acids. When using a precursor according to an embodiment of the present invention, there are less by-products generated for every mole of peroxy acid generated. Further, a smaller weight of the precursor provided by the present invention is required to generate a mole of peroxy acid than when using a prior art material and/or method. The acyl precursors provided by an embodiment of the present invention are generally more water-soluble than ASA, relatively inexpensive to manufacture, and consume less weight of acyl precursor per mole of peroxy acid generated than the corresponding ASA.
Uses for the solutions provided by the embodiments of the invention include, without limitation: emergency disinfection of wounds by mixing dry powder with water; disinfection of surgical facilities and medical treatment rooms; chemical sterilization of surgical equipment and instruments, particularly endoscopes; disinfection of medical devices; disinfection of animal enclosure areas such as used by horses, cattle, dogs, cats, etc.; remediation of mold in buildings, the contents of buildings; disinfecting plants and foodstuffs, including meats, vegetables, and fruits; disinfection of surfaces from vegetative bacteria, molds, fungi and their spores, especially for remediation in non-line-of-slight applications; and liquid disinfectants of equipment such as tanks, passenger cars, all military vehicles, aircraft, and related equipment.